In scientific medical practice the clinician must determine the anatomical location of an infection, the nature of the causative agent and the drug susceptibility/resistance pattern. The routine cultural methods require a few days to identify the pathogenic agent. Rapid identification of the pathogen is helpful in prescribing proper antimicrobial medication.
Microbes are rapidly changing or evolving either because of sudden or gradual increase in drug resistance or through episomal transmission of drug resistance (resistance transmission factor or resistance factor). The list of antimicrobial drugs is constantly increasing and the choice of which drug to use in treating infections is a difficult one.
Since the recent introduction of the Kirby-Bauer scale in antimicrobial therapy by the Food and Drug Administration, the physician is warned indirectly to make bacterial cultures and to determine the drug susceptibility-resistance pattern of pathogens. All package inserts of antimicrobial drugs contain the range of effectiveness of that drug in the treatment of various pathogenic bacteria.
Numerous rapid chemical and bacteriological methods of diagnosis of urinary tract infection have been devised. The most primitive procedure is Gram or methylene blue stain of urinary sediment. It is claimed that a colony count of more than 100,000 bacteria per ml. shows bacteria in the smear.
The principle in the nitrite (Griess) test is the reduction of nitrate to nitrite by bacteria in urine. The triphenyltetrazolium chloride test (Uroscreen) is based on reduction of triphenyltetrazolium by bacteria to formazan which is a red precipitate. In the catalase test, bacteria and blood cells liberate oxygen from hydrogen peroxide. In the PathoTec test, chemically treated strips of filter paper are dipped into cultures of bacteria to identify phenylalanine deaminase, lysine decarboxylase, urease, citrase, indole and acetyl methyl carbinol production by bacteria. The enterotube method is a modification of PathoTec in which 8 media in a tube are inoculated from a bacterial culture to determine dextrose/dulcitol fermentation, lysine decarboxylation, urease, citrase, indole and H.sub.2 S production. In R/B differential system for identification of Enterobacteriaceae, bacterial culture is inoculated to tube 1 for lactose/dextrose fermentation, phenylalanine deaminization, lysine decarboxylation and H.sub.2 S production; while tube 2 is used for motility, indole production and lysine decarboxylation. In the Urocult test, medium is coated inside the tube which is filled with urine and then decanted. Sturdy bacteria grow on this crude medium and the colony count is very inaccurate. Another test is based on the production of adenosine triphosphate but non-bacterial adenosine triphosphate must be first eliminated. In the Bacti Lab test urine is spread on blocks of media (blood agar, eosin methylene blue, MacConkey's agar, triple sugar iron agar and urea agar) for fast-crude identification and colony count. UniTect medium is a modification of the Bacti Lab test. In the Unibac System a plate containing eosin methylene blue, blood agar, mannitol salt agar and mycobiotic dextrose agar is inoculated; while Mueller-Hinton medium is used for drug susceptibility.
The foregoing described chemical and bacteriological methods of diagnosis of urinary tract infection are useful advances, but these methods are not entirely satisfactory as either being not sufficiently rapid or not providing accurate and reliable data.
Accordingly, it is an object of the present invention to provide a method for rapid and accurate identification of uropathogenic bacteria and colony count determination.
It is another object to provide an article of manufacture which is inexpensive and disposable, and which is adapted for rapid identification of uropathogens.